The Relationship among Homocysteine, Bilirubin, and Diabetic Retinopathy

BACKGROUND Diabetic retinopathy is a common microvascular complication of diabetes mellitus (DM) and the leading cause of blindness in adults. Homocysteine, a risk factor with toxic effects on vascular endothelial cells, and bilirubin, a protectant with antioxidant and anti-inflammatory properties on the vasculature, have been reported to be linked to vaso-occlusive disorders. Therefore, the author of the present study investigated the association between the levels of plasma homocysteine and serum total bilirubin and the incidence of diabetic retinopathy as a chronic microvascular complication in patients with type 2 diabetes mellitus (T2DM). METHODS A total of 102 patients with T2DM who visited our hospital from January 2009 to January 2010 were assessed. RESULTS Of the 102 patients, the prevalence of diabetic retinopathy was 67 cases (65.7%) according to clinical ophthalmic examination. The duration of DM (P<0.001), age (P=0.003), fasting blood glucose (P=0.045) and urine albumin-creatinine ratio (P=0.015) in univariate analysis and plasma homocysteine level (P=0.038), duration of DM (P=0.001), and total bilirubin level (P=0.012) in multiple logistic regression analysis were statistically significantly associated with the incidence of diabetic retinopathy. CONCLUSION The present study indicates that homocysteine and bilirubin may be useful biomarkers for increased risk of diabetic retinopathy since retinopathy in patients with T2DM was linked to higher plasma homocysteine level and decreased serum total bilirubin level.